which had bitterly resisted American pressure to open the country's nuclear facilities to inspection, is using its religious influence to rally support for an agreement with the West to foreswear the development of nuclear weapons.

Led by Ayatollah Ali Khamenei, the nation's "supreme leader," Iranian clerics have repeatedly declared that Islam forbids the development and use of all weapons of mass destruction.

"The Islamic Republic of Iran, based on its fundamental religious and legal beliefs, would never resort to the use of weapons of mass destruction," Khamenei said recently. "In contrast to the propaganda of our enemies, fundamentally we are against any production of weapons of mass destruction in any form."

These and other statements from senior Iranian clerics appear to have bolstered domestic support for an agreement signed Oct. 21 with Britain, France and Germany that will allow international inspections of the country's nuclear program.

Bush administration officials and many Western arms experts remain skeptical of Iran's intentions, believing that the country is using its civilian nuclear program to hide a covert weapons program. They cite intelligence, such as the discovery of enriched uranium at two Iranian sites, to support their contention.

But other analysts, diplomats and Iranian clerics say that the unexpectedly strong pronouncements from Khamenei and others have produced a strong domestic consensus on the issue that would be hard for the ruling religious establishment to reverse. "I haven't seen anything like it, this kind of consensus," said one Western diplomat in Tehran. "Even if you view it cynically, as I do, religion seems to be the rhetorical glue that holds it all together."

In an interview, one of Khamenei's top aides hinted that while some prohibited nuclear weapons work may have been carried out, the government has decided to put a stop to it.

"Those in Iran who clandestinely believed they could develop nuclear weapons have now been forced to admit that is forbidden under Islam," said Hussein Shariatmadari, who is president of the Kayhan chain of newspapers, controlled by Khamenei, and an unofficial spokesman for the supreme leader.

Shariatmadari added that there also are practical considerations behind the theological ban.

"A nuclear bomb is not like wine -- you can make in your home and hide it easily," he said. "No, the IAEA can find anything. So if you can't use it, why have it?"

The apparent switch in attitude is evident in Iranian holy city of Qom, the headquarters of Iran's Shiite establishment, with several highly influential seminaries that provide platforms for clerics to speak on issues spiritual and temporal.

A medium-size city in the desert south of Tehran, Qom is also the heart of the nation's cultural conservatism. Turbaned mullahs and throngs of pilgrims fill its huge, elaborately blue-tiled Masoumeh shrine and its scores of mosques. Nearly all women in Qom wear the chador -- a full-length, tentlike black gown covering all but the face -- unlike the common practice in other Iranian cities, where most women simply wear a hejab, or headscarf, the minimum required by law.

Grand Ayatollah Yusef Saanei, one of the highest-ranking clerics in Iran, said in an interview: "There is complete consensus on this issue. It is self- evident in Islam that it is prohibited to have nuclear bombs. It is eternal law, because the basic function of these weapons is to kill innocent people. This cannot be reversed."

Saanei said clerical authorities have quietly expressed opposition to the development of weapons of mass destruction for many years, and he described it as the reason that Iran never retaliated with chemical weapons when Saddam Hussein used them to kill Iranian troops and Iran-backed Kurds during the 1980- 88 Iran-Iraq war.

"You cannot deliberately kill innocent people," he said.

Some diplomats privately dismiss such statements, pointing to alleged Iranian government support for such organizations as the Palestinian Islamic Jihad and other groups whose suicide bombings have killed hundreds of innocent civilians.

"I think the theological line is merely used to justify decisions they made for other reasons," said a second Western diplomat in Tehran. "They could discard it and replace it with another fatwa if they need to."

Even some religious leaders agree that there may be more pragmatic reasons for the new approach.

"It was surprising that the supreme leader cast it in religious terms," said Fazal Miboudi, a mullah who is professor of political science at Mofid University in Qom. "It showed that the threat was too much, the danger that the country would be brought before the U.N. Security Council and punished. He had to get involved, and that is how he could justify his involvement."

Miboudi and several diplomats said that the mullahs' anti-nuclear line emerged in the summer, when the mullahs took over negotiations with the Europeans from the elected government of reformist President Mohamed Khatami. The Iranian delegation was led by Hassan Rowhani, a cleric who is chairman of the National Security Council and who reports directly to Khamenei.

Diplomats said later that although Rowhani was a tough negotiator, he made a major contribution to the pact by publicly repeating that Khamenei opposednuclear weapons and supported signing the pact.

Asked whether the ayatollahs could simply rip up their fatwa one day and issue a new ruling blessing the development of nuclear weapons, Miboudi said any reversal of such a high-profile issue would require years of awkward theological maneuvering.

"There is room for maneuver in Islam. Things can be haram (forbidden) one day and halal (acceptable) later on. But this takes time," he said.Whether Iran's apparent restraint on nuclear weapons development will continue is an all-important question as the West monitors Iran's compliance with the agreement.

While the pact requires Iran to temporarily suspend the enrichment of uranium, which is needed both to run nuclear power plants and for nuclear weapons payloads, it is widely expected that Iran will resume its enrichment program after the IAEA inspections system has shown some progress. In the meantime, Iran also will be allowed to continue construction of the centrifuges needed for enrichment, as well as other equipment and research work.

Despite the religious pronouncements, analysts in Washington and elsewhere remain deeply concerned that once Iran has a major civilian nuclear program operating with international approval and with large, domestically produced stocks of nuclear fuel, its leaders could abandon the weapons ban, break out its enriched uranium and build bombs quickly.

"I doubt the fear of God will keep the mullahs from building the bomb if they really want to," said a diplomat. "But we're hoping it may slow them down a bit."